Question

Most of the examples I’ve found for Automapper use the static Mapper object for managing type mappings. For my project, I need to inject an IMapperEngine as part of object construction using StructureMap so that we can mock the mapper in unit tests so we can’t use the static mapper. I also need to support configuring AutoMapper Profiles.

My question is how can I configure the StructureMap registry so that it can supply an instance of IMappingEngine when an instance of MyService is constructed.

Here is the Service constructor signature:

public MyService(IMappingEngine mapper, IMyRepository myRepository, ILogger logger)

And here is the StructureMap Registry

public class MyRegistry : StructureMap.Configuration.DSL.Registry
{
    public MyRegistry()
    {
        For<IMyRepository>().Use<MyRepository>();
        For<ILogger>().Use<Logger>();
        //what to do for IMappingEngine?
    }
}

And the profile I want to load

public class MyAutoMapperProfile : AutoMapper.Profile
{
    protected override void Configure()
    {
        this.CreateMap<MyModel, MyDTO>();
    }
}

Answer 1

The Mapper class has a static property Mapper.Engine. Use this to register the engine with the container:

For<IMappingEngine>().Use(() => Mapper.Engine);

If you need to load your profiles before injecting the engine I would insert that configuration code alongside the above snippet.

---

Update

Your custom registry would look like this

class MyRegistry : Registry
{
  public MyRegistry()
  {
    For<IMyRepository>().Use<MyRepository>();
    For<ILogger>().Use<Logger>();

    Mapper.AddProfile(new AutoMapperProfile());
    For<IMappingEngine>().Use(() => Mapper.Engine);
  }
}

This code runs once in your bootstrapper and any dependency of type IMappingEngine will afterwards be served with the value of the static property Mapper.Engine which is configured using your custom AutoMapperProfile.